Gnome display manager crashes on clicking show desktop button

Thank you for taking the time to report this bug and helping to make Ubuntu better. However, your crash report is either missing or challenging to deal with as a ".crash" file. Please follow these instuctions to have apport report a new bug about your crash that can be dealt with by the automatic retracer.

If you are running the Ubuntu Stable Release you might need to enable apport in /etc/default/apport and restart.

If you are using Ubuntu with the Gnome desktop environment - launch nautilus and navigate to your /var/crash directory and double click on the crash report you wish to submit.

I'm closing this bug report since the process outlined above will automatically open a new bug report which can then dealt with more efficiently. Thanks in advance for your cooperation and understanding.

 This is very annoying because you are losing your work if is not saved...
I can't tell you what is the problem, but I manage to replicate the method that makes the gnome to crash.
You must have firefox with a webpage that have flash, and another program (in my case the console). If I minimize the firefox window several times ... the gnome crashes...

I manage to recrod this on my phone and put it online at : http://blog.geod.ro/crash.tar.gz

p.s. i've enabled apport, but is not showing error, and crash dir is empty...

Please help me with this. THIS IS THE SINGLE AND MOST ANNOYING BUG IN UBUNTU....

Thank you.